Embodied energy
The embodied energy (carbon) of a building material can be taken as the total primary energy consumed (carbon released over its life cycle). This would normally include (at least) extraction, manufacturing and transportation. Ideally the boundaries would be set from the extraction of raw materials (including fuels) until the end of the products lifetime (including energy from manufacturing, transport, energy to manufacture capital equipment, heating and lighting of factory, maintenance, disposal etc.), known as ‘Cradle-to-Grave’. It has become common practice to specify the embodied energy as ‘Cradle-to-Gate’, which includes all energy (in primary form) until the product leaves the factory gate. The final boundary condition is ‘Cradle –to-Site’, which includes all of the energy consumed until the product has reached the point of use (ie the building site).
The figures included in the following table are a much-shortened and abbreviated adaptation of a survey published by the Sustainable Energy Research Team (SERT) of the University of Bath. The survey, ‘Inventory of Carbon & Energy (ICE)’ V1.6a, was compiled and written by Prof. Geoff Hammond & Craig Jones, 2008. The full detailed survey, complete with original data, methodology and notes, is available from www.bath.ac.uk/mech-eng/sert/embodied/
The figures are based on a ‘Cradle-to-Gate’ analysis of publicly available information.
| Material | Energy MJ/kg |
Carbon kg CO2/kg |
Density kg /m3 |
| Aggregate | 0.1 | 0.005 | 2240 |
| Concrete (1:1.5:3 eg in-situ floor slabs, structure) | 1.11 | 0.159 | 2400 |
| Concrete (eg in-situ floor slabs) with 25% PFA RC40 | 0.97 | 0.132 | |
| Concrete (eg in-situ floor slabs) with 50% GGBS RC40 | 0.88 | 0.101 | |
| Bricks (facing) | 8.2 | 0.52 | 1700 |
| Bricks (common) | 3.0 | 0.22 | 1700 |
| Concrete block (150mm medium weight) | 0.71 | 0.08 | 1900 |
| Aerated block | 3.50 | 0.30 | 750 |
| Rammed earth | 0.45 | 0.023 | 1460 |
| Limestone block | 0.85 | 2180 | |
| Marble | 2.00 | 0.112 | 2500 |
| Cement mortar (1:3) | 1.40 | 0.213 | |
| Steel (virgin) | 35.30 | 2.75 | 7800 |
| Steel (recycled) | 9.50 | 0.43 | 7800 |
| Steel (typical virgin/recycled) | 24.40 | 1.77 | 7800 |
| Timber (general) | 8.50 | 0.46 | 480 - 720 |
| Glue laminated timber | 12.00 | 0.65 | |
| Sawn hardwood | 7.40 | 0.47 | 700 - 800 |
| Cellular glass insulation | 27.00 | ||
| Cellulose insulation (loose fill) | 0.94 – 3.3 | 43 | |
| Cork insulation | 26.00* | 160 | |
| Glass fibre insulation (quilt) | 28.00 | 1.35 | 12 |
| Flax insulation | 39.50 | 1.70 | 30* |
| Rockwool (slab) | 16.80 | 1.05 | 24 |
| Polystyrene insulation | 88.60 | 2.50 | 15 – 30* |
| Polyurethane insulation | 72.10 | 3.00 | 30 |
| Woodwool board insulation | 20.00 | 0.98 | |
| Wool (recycled) insulation | 20.9 | 25* | |
| Straw bale | 0.24 | 0.01 | 100 – 110* |
| Mineral fibre roofing tile | 37 | 2.70 | 1850* |
| Slate (UK – imported) | 0.1 – 1.0 | 0.006 – 0.056 | 1600 |
| Clay tile | 6.50 | 0.46 | 1900 |
| Concrete tile | 2.0 | 0.215 | 2100 |
| Aluminium (general & incl 33% recycled) | 155 | 8.24 | 2700 |
| Bitumen (general) | 47 | 0.48 | |
| Hardboard | 16.00 | 0.86 | 600 - 1000 |
| MDF | 11.00 | 0.59 | 680 – 760* |
| OSB | 9.50 | 0.51 | 640* |
| Plywood | 15.00 | 0.81 | 540 - 700 |
| Plasterboard | 6.75 | 0.38 | 800 |
| Gypsum plaster | 1.80 | 0.12 | 1120 |
| Glass | 15.00 | 0.85 | 2500 |
| PVC flooring | 65.64 | 2.29 | 1200 |
| PVC composite tiles | 13.70 | 1600* | |
| Linoleum | 25.00 | 1.21 | 1200 |
| Terrazzo tiles | 1.40 | 0.12 | |
| Ceramic tiles | 9.00 | 0.59 | 2000 |
| Nylon carpet | 67.90 - 149 | 3.55 – 7.31 | |
| Wool carpet | 106.00 | 5.48 | |
| Wallpaper | 36.40 | 1.93 | |
| Wood stain / varnish | 50.00 | ||
| Concrete paving | 1.24 | 0.127 | 2000* |
| Asphalt paving | 2.41 | 0.14 | 2100 |
| Vitrified clay pipe (DN 500) | 7.86 | 0.53 | |
| Iron (general & average) | 25 | 1.91 | 7870 |
| PVC pipe | 67.5 | 2.5 | |
| Copper (average incl. 46% recycled) | 48 | 3.01 | 8600 |
| Lead (incl 61% recycled) | 25 | 1.33 | 11340 |
| Ceramic sanitary ware | 29.00 | 1.48 |
Windows
| Material | Energy MJ/m2 |
Carbon kg CO2/m2 |
| Aluminium 2x glazed, argon filled, window | 5470 | 279 |
| PVC 2x glazed, argon filled, window | 2310 | 118 |
| Aluminium clad timber, 2x glazed, argon filled, window | 1200 | 61 |
| Timber 2x glazed, argon filled, window | 360 | 18 |
Paint
| Material | Energy MJ/m2 |
Carbon kg CO2/m2 |
| Paint (2 coats) | 20.4 | 1.06 |
Photovoltaic (PV) cells
| Material | Energy MJ/m2 |
Carbon kg CO2/m2 |
| Monocrystalline (average) | 4750 | 242 |
| Polycrystalline (average) | 4070 | 208 |
| Thin film (average) | 1305 | 67 |
Key: * - figures byGreenSpec obtained from publicly available information
Further information
• Sustainable Energy Research Team (SERT), - University of Bath - (bit.ly/biRxxM )
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